RFR: 8272215: Add InetAddress methods for parsing IP address literals [v2]

[Aleksei Efimov]

On Thu, 5 Oct 2023 22:25:23 GMT, Mark Sheppard <msheppar at openjdk.org> wrote:

> That is to say, a literal string representing an address is essentially the same as an array of bytes representing an address

 A literal IP address string can specify the same address in [multiple formats](https://docs.oracle.com/en/java/javase/20/docs/api/java.base/java/net/InetAddress.html#textual-representation-of-ip-addresses-heading), a byte array supports only one - an array of bytes, with length equal to 4 for IPv4 addresses, and to 16 for IPv6 addresses.

> Ceist agam ort:
> Why is it necessary that the subclasses Inet4Address and Inet6Address have an explicit public method for a getByAddress approach?

The idea of this change is to add three methods capable of parsing a string as an IPv4, IPv6 or any IP literal address. The explicit methods needs to be added to all three classes irrelevant to their naming.

> Or have I misconstrued your statement: "Overrides existing method in InetAddress, but adds new method to Inet4Address and Inet6Address." ?
> But this is the case for the current "ofLiteral" solution presented in the PR, in that each of the derived classes Inet4Address and Inet6Address have added new static public methods.

You are right that the statement is a bit vague, yes. What was meant there that overloading `InetAddres` method, and adding new methods to `Inet4Address` and `Inet6Address` would introduce a bit confusing API structure. All three classes for both approaches would look like:

### ofLiteral approach

// New methods
InetAddress.ofLiteral(String)
Inet4Address.ofLiteral(String)
Inet6Address.ofLiteral(String)


### getByAddress approach

// Existing methods with `address` being a byte array
InetAddress.getByAddress(String, byte[])
InetAddress.getByAddress(byte[])

// New methods with `address` being a literal  
InetAddress.getByAddress(String) <-- overloaded method
Inet4Address.getByAddress(String) <-- new and not overloaded method
Inet6Address.getByAddress(String) <-- new and not overloaded method

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PR Comment: https://git.openjdk.org/jdk/pull/15775#issuecomment-1750435491